Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8910562 | Geochimica et Cosmochimica Acta | 2018 | 50 Pages |
Abstract
In general, moderately volatile elements with 50% condensation temperatures (TC) ranging from 1250â¯K to 800â¯K show an increasing depletion, whereas 11 moderately volatile elements with 50% TC between 800â¯K and 500â¯K are unfractionated from each other in most samples. Their extent of depletion is characteristic for the different chondrite groups. Because of this well-defined “hockey stick” pattern, we propose to divide the moderately volatile elements into two subgroups, the 'slope volatile elements' and the unfractionated 'plateau volatile elements' with lower TC. Notably, the abundances of plateau volatile elements exhibit a co-variation with the matrix abundances of the respective host meteorites. Carbonaceous chondrite matrices are likely mixes of: (i) CI-like material and (ii) chondrule-related matrix. Chondrule-related matrix is expected to be depleted in volatile elements relative to CI and likely formed contemporaneously with chondrules, leading to chondrule-matrix complementarity. The addition of CI-like material only changed the absolute elemental concentrations of bulk matrix and bulk chondrite, while refractory and main component element ratios such as Mg/Si remain unaffected. Such a model can also account for the co-existence of low temperature CI-like material and high temperature chondrule and chondrule-related matrix. However, elevated volatile element abundances observed in chondrules still provide a challenge for the model as proposed here.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geochemistry and Petrology
Authors
Ninja Braukmüller, Frank Wombacher, Dominik C. Hezel, Raphaelle Escoube, Carsten Münker,